Effects of butanedione monoxime on neuromuscular transmission.

1. The amplitude of endplate potentials was increased by concentrations of butanedione monoxime (BDM, 5-20 mM) that typically caused muscle paralysis. 2. Although BDM slowed the decay of spontaneous miniature endplate currents, the effect was insufficient to explain most of the large increase in amplitude of endplate potentials. 3. The quantal content of endplate potentials was increased by BDM in a reversible, concentration-dependent manner. 4. The frequency of miniature endplate potentials was not changed by 10 mM BDM in the presence of normal or raised potassium concentrations, indicating that BDM does not change quantal content by a direct effect on calcium channels or on steady-state intracellular calcium concentration. 5. A change in the time course of the extracellularly recorded nerve terminal action potential caused by BDM was similar to the change produced by 4-aminopyridine (4-AP). 6. The increase in quantal content produced by BDM was only slightly reduced in the presence of 1 mM tetraethylammonium (TEA) but was significantly reduced in the presence of 0.5 to 1 mM 4-AP. 7. It was concluded that BDM blocks a 4-AP-sensitive potassium conductance in motor nerve terminals and, by increasing the duration of the action potential in this way, increases evoked transmitter release.     

Bilateral newborn testicular torsions]

A case of bilateral spermatic cord tension in a neonate is reported. Clinical findings are compared with those in 22 previously published cases. Obstetrical history is usually unremarkable. Torsion occurs prior to birth or immediately after birth. The two cords are involved simultaneously or successively. Edema of the scrotum is found in recent spermatic cord tension, whereas subsequently the tests are extremely hard and occasionally severely atrophied. Prognosis is poor since castration or poor testicular viability was the outcome in most cases.     

Detection of Epstein Barr virus in an hepatic leiomyomatous neoplasm in an adult human immunodeficiency virus 1-infected patient

We report the first case of a human immunodeficiency virus (HIV)-related primary hepatic leiomyoma in an adult patient. The diagnosis was made at autopsy and confirmed by immunohistochemistry. Epstein Barr virus (EBV) was identified in tumour cells by in situ hybridization. Review of the literature revealed 13 cases of visceral myogenic tumours occuring in acquired immunodeficiency syndrome children, and only 2 cases in adults. One was a spinal epidural leiomyoma, the other multiple smooth muscle tumours of the colon and adrenal gland. This is the first report of EBV in smooth muscle neoplastic cells in an HIV-infected adult patient.     

Monoclonal antibodies against respiratory syncytial virus and their use for rapid detection of virus in nasopharyngeal secretions.

We developed five monoclonal antibodies against respiratory syncytial virus. Three of these (23A3, 12A4, and 18B2) were used in an indirect fluorescent antibody test, and the results were compared with those of a similar indirect fluorescent test with commercial anti-respiratory syncytial virus serum. The results obtained with antibody 18B2 and commercial anti-respiratory syncytial virus serum were identical, whereas with antibodies 23A3 and 12A4 the incidence of positive identifications was around 50%.     

Pulsed-field gel electrophoresis of NotI digests of leptospiral DNA: a new rapid method of serovar identification.

Fingerprints for 72 reference serovar strains of pathogenic Leptospira spp. were obtained by pulsed-field gel electrophoresis (PFGE) following NotI restriction digests of the chromosome. These strains included the serovar reference strains of serogroups Australis, Ballum, Bataviae, Grippotyphosa, Panama, Pomona, and Pyrogenes. Sixty-four serovars could be identified by a unique NotI restriction profile. The remaining serovars were differentiated by chromosomal digestion with SgrAI. These included four serovars from serogroup Australis, two serovars from serogroup Ballum, and two serovars from serogroup Bataviae. Thirteen of 18 recent clinical isolates identified by microagglutination test and cross-adsorption procedure were correctly typed by PFGE. The results indicate that PFGE, which is considerably more rapid than serology, should be useful for identification and epidemiological studies.     

Interaction of Neisseria meningitidis with a polarized monolayer of epithelial cells.

An important step in the pathogenesis of Neisseria meningitidis is the crossing of two cellular barriers, one in the nasopharynx and one in the brain. To approach the mechanisms by which this bacterium can achieve these goals, we studied the interactions between N. meningitidis and a monolayer of polarized tight junction-forming T84 cells grown on filter units. A capsulated, piliated, Opa-, and Opc- N. meningitidis strain is shown to be capable of adhering to and crossing this monolayer several orders of magnitude more efficiently than an isogenic nonpiliated derivative. This bacterial interaction does not affect the barrier function of tight junctions, as assessed by (i) the absence of modification of the transepithelial resistance, (ii) the lack of increase of [3H]inulin penetration across the monolayer, and (iii) the absence of delocalization of ZO-1, a tight junction protein. Electron microscopy studies and confocal examinations demonstrated that N. meningitidis (i) induces cytoskeletal rearrangements with actin polymerization beneath adherent bacteria, (ii) is intimately attached to the apical membrane of the cells, and (iii) can be internalized inside cells. Immunofluorescent staining with antipilus antibodies showed evidence that meningococcal piliation was dramatically reduced at later time points of bacterial cell interaction compared to the early phase of this interaction. In addition, adhesive bacteria recovered from an infected monolayer are piliated, capsulated, Opa-, and Opc-, a phenotype similar to that of the parental strain. Taken together, these data demonstrate that following pilus-mediated adhesion, N. meningitidis is involved in an intimate attachment which requires a bacterial component different from Opa and Opc and that meningococci cross a monolayer of tight-junction-forming epithelial cells by using a transcellular pathway rather than a paracellular route.     

Immunohistochemical detection of Fas and Fas ligand in sarcomatoid renal cell carcinoma

Sarcomatoid renal cell carcinomas (SRC) are rare neoplasms associated with a very poor prognosis. The aim of this study was to evaluate biomarker expression and clinical significance in this uncommon renal cancer. Cytokeratin, epithelial membrane antigen, vimentin, desmin, smooth muscle actin, CD34, S-100 protein, MIB 1, p53, Fas and Fas ligand immunohistochemical expression was investigated in seven renal cell carcinomas with sarcomatoid changes. No significant difference between sarcomatoid and nonsarcomatoid areas was observed with the different biomarkers, excepted for Fas ligand. Fas expression was diffuse in sarcomatoid and nonsarcomatoid areas. However, Fas ligand had a higher expression in sarcomatoid in comparison to nonsarcomatoid areas. Our results showed that Fas and Fas ligand are both expressed in renal cancer. We suggest that the aggressive behavior of sarcomatoid carcinoma may be related to a higher expression of Fas ligand by tumor sarcomatoid cells. These findings may indicate that Fas ligand is a possible therapeutic molecular target for treatment of SRC.